I'm not saying you're not going to drive confusion by overloading context, but the number of tokens required to trigger that failure mode in opus is going to be a lot higher than the number for gpt-oss-20b.
I'm pretty sure a model that can run on a cellphone is going to cap out it's context window long before opus or mythos would hit the point of diminishing returns on context overload. I think using a lower quality model with far fewer / noisier weights and less precise attention is going to drive false positives way before adding context to a SOTA model will.
You can even see here, AISLE had to print a retraction because someone checked their work and found that just pointing gpt-oss-20b at the patched version generated FP consistently: https://x.com/ChaseBrowe32432/status/2041953028027379806